Eel trap



L. T. CRITCHLOW EEL TRAP Filed Sept. 30,1944

INVENTOR Patented May 11, 1948 UNITED STATES PATENT OFFICE.

Continuation of application Serial No. 515,043,

This application September 30, 1944, Serial N0. 556,609

December 20, 1943.

3 Claims. 1 .The present application is a continuation of application Ser. No. 515,043, filed Dec. 20, 1943, now abandoned.

The lamprey, more commonly known as the lamprey eel, has in recent time achieved some commercial importance because of the oil and meal obtained therefrom when duly processed.

Lampreys are found in almost all waters and travel up and over obstacles by use of the sucker mouth with which they are equipped on the end of the head.

By the use of this sucker mouth the eel can travel over any surface that is sufficiently smooth and has water flowing thereover, and they collect in numbers sufficient for gathering in many artificial waterways, as fishways or fish ladders, and in various types of hydraulic installations which receive water flowing from its natural course. In the latter case they sometimes collect in such large numbers as to interfere materially with, or actually prevent closing of a gate valve or other operation of the plant.

When lampreys collect in such numbers it has heretofore been the practice to scoop them out by hand labor, which of course, means that it has been a slow and costly procedure.

It is, therefore, the object of the present invention to utilize the peculiar mode of transportation of the lamprey to lure it into a receptacle from which there is no escape.

It is also an object of the invention to provide means for the purpose indicated that will be extremely simple in form and construction, economical to manufacture, and highly efficient in its practical application.

In the drawing:

Figure 1 is a vertical transverse sectional view through a portion of a fishway embodying my invention.

Figure 2 is an inside elevation of the structure shown in Figure 1, with parts broken away.

Figure 3 is an elevation of a portion of the outside of the structure shown in Figure l with parts broken away and in section.

Numberless ways might be conceived for carrying out my invention, but one way in which it may be applied to a fishway l in which water flows at 2, is to crown the fishway side wall with a structure 3 that is in the form of a truncated cone in transverse cross-section.

The entire inwardly directed surface 4 of memher 3 is smooth and its lower edge coincides with the top edge of the wall I, which also is smooth as at 5.

The top portion 6 of member 3 is also smooth.

.2 The outwardly directed surface I of portion 3 may be left unsurfaced and rough and is extended downwardly on the outer side of wall I to form wall 8, thence outwardly in a horizontal plane to form wall 9, thence upwardly to form wall In and provide a trough I2 in which water flows at l3. The top edge of surface I is smooth as at I4 to enable the eels to travel thereover, the entire remaining part of surface 1 and the en; tire inner surfaces of walls 8, 9 and Ill may be given a definitely rough surfacing 'by applying thereto a covering of screen as H.

Supported in spaced relation to the top portion 6 and longitudinally thereof on brackets I5 is a water conduit l6 provided with holes I! along its lower portion so that water flowing through the conduit will discharge downwardly over the smooth surfaces 4, 5 and 6 for the purpose hereinafter described.

Lampreys moving up the fishway through the water 2 are attracted to the wall I by the water flowing thereover as at l8, and obeying their natural instincts they proceed to travel up the wall surface 5 and surface 4 of the crown member 3. This is accomplished by use of the suction mouth with which they are equipped, attaching it to the smooth wall each time they throw themselves forward, usually a distance of from a quarter to a half inch. But when the lampreys have successfully reached the top of the wall and crown 3 and move over the top 6 and. move forwardly to place their suction mouths on the new places on the rough surface of wall 1, they are unable to make suction contact with the rough surface, and being sufficiently far over the top to be unbalanced they fall into the trough ii. The trough [2 being rough as described the lampreys are unable to get a grasp on its surface and are carried to a suitable point for removal.

Clearly the invention is not confined to the specific form shown and described, since the principle involved can be used to trap lampreys in a natural stream or wherever they may be found; and various changes and modifications may be made within the scope of the claims attached hereto without departing from the spirit of the invention.

I claim:

1. A lamprey eel trap comprising a structure having a smooth surface leading upwardly from a body of water and having water flowing thereover, and a roughened surface leading downwardly from the smooth surface, and means disposed to receive eels falling from the said roughened surface.

2. A lamprey eel trap comprising a structure having a smooth surface leading angularly upward from a. body of water and terminating in a narrow smooth surface extending laterally therefrom and having water flowing downwardly thereover, and a rough surface leading angularly downwardly from the smooth surface, and a receptacle disposed to receive eels falling from the said rough surface.

3. A lamprey eels trap comprising a structure having a smooth surface leading angularly upward from a body of Water and terminating in a narrow smooth surface extending laterally therefrom, a water pipe disposed thereover having perforations along its under side to direct a flow 15 of water over said smooth surface, and a rough I surface leading angularly downward from the smooth surface, and a receptacle disposed to receive eels falling from the said rough surface.

LEG T. CRITCHLOW. 20

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS 

